Stereoscopic 3-dimensional imaging systems have been known for quite some time and produce overlaid images that are projected on a screen and viewed by the use of special eyeglasses of which the lenses are conditioned so that each eye views a distinct one of the overlaid images to view a subject from different angles and thereby create a perception of depth of field. Usually the stereoscopic film is produced by utilizing two cameras to obtain two different films each having a different perspective of the subject being filmed. With such a system the positioning of the cameras becomes very critical and the production of such films is therefore time-consuming, costly and has limited applications. Such techniques have also found technical applications and particularly in the field of endoscopy and microscopy.
When the subject being filmed is far away, the distance between the cameras must be augmented considerably in order to obtain a stereoscopic effect to simulate a depth of field of what would be naturally seen by the human eyes. However, if a stereoscopic film had to be produced from, for example, an aircraft flying at an altitude of 1000 meters, with the subject on the ground, the distance between two cameras would have to be several meters. However, it is practically impossible to separate two cameras in an aircraft having sufficient spacing to produce stereoscopic images of such subject as the separation of the cameras is restricted by the length of the fuselage of the aircraft.
In U.S. Pat. 4,807,024, issued Feb. 21, 1989, to the University of South Carolina, there is described an apparatus and a method for producing 3-dimensional images by using a single camera mounted on a platform moving at constant velocity and spacing with respect to a subject to be imaged. This system is characterized in that the 3-dimensional images can be viewed without the use of special eyeglasses and that the images on the screen are displaced from the top to the bottom of the screen. This system alternates the frames of the films at an average frequency of 10 frames per second but this could vary between 4 and 30 frames. Two work prints are placed in an optical printer and aligned for printing with corresponding images in the two prints offset from each other by a sufficient number of frames so that the resulting print contains images that evolve in time with alternating view points that differ in vertical parallax. It is disclosed that by employing a video camera and video processing, high quality 3-dimensional images may be generated in near real-time and viewed without the use of special glasses or other aids.